An experiment to study influence of nitrogen (N) and potassium (K) on new rice varieties MR 269 and MR 284 has been carried out in Parit 12 Sungai Nibong, Sekinchan, 45400, Sabak Bernam, Selangor from February 2012 to January 2013. Compatibility tests need to be carried out on current fertilizer recommendation towards these new rice varieties. There are three rates used in this experiment which are 0, 100 and 200 kg/ha for both N and K fertilizer. The experimental design used in this experiment is Randomized Complete Block Design (RCBD) with 3 replications. A set of 54 small plots were erected with 4 m x 4 m in size. Manual Teknologi Penanaman Padi Lestari is used as crop management guideline for this experiment. Results indicated no significant interaction between N and K on yield of the newly tested rice varieties. The rice yield was significantly affected by N but not by K. Results suggest that there is significant interaction between cropping season and N towards rice yield. Analysis showed that fertilizer application of N up to 200 kg/ha contributed to higher yield in first season (Off-season). However, yield increment in season 2 (main season) only took place up until N fertilizer application at 100 kg/ha and began to drop when subsequent additional of 200 kg/ha. This study indicated that number of panicle and number of seed per panicle had positive influence to the rice yield.

The research was conducted at MARDI Seberang Perai research plot during main-season 2011/2012 and off-season 2012. Varieties such as MR 272, MR 278, MR 283 and MR 284 showed high yield potential as compared to the control varieties namely MR 211, MR 219, MR 253 and MR 263. According to correlation analysis, traits such as flag leaf width (r = 0.36, p = 0.01), percentage filled grain (r = 0.43, p = 0.002) and spikelets number/panicle (r = -0.43, p = 0.002) showed association toward yield potential. As a result, high rate of photosynthesis is depend to high leaf surface area. In addition, low number of spikelets /panicle can enhance the grain filling.

Effect of different rates of N and K on yield and yield components for MR 269 and MR 278 was conducted in Sungai Limau, Yan, Kedah during off season 2012 and main season 2012/2013. The treatment consisted of factorial combination of two rice varieties (MR269 and MR278) with 3 different rates of N and K2O (0, 100, 200 kg/ha) laid out in randomized complete block design and replicated three times. In off-season of 2012, MR 269 and MR 278 responded positively to yield performance (t/ha) when N rate was 100 kg/ha and 200 kg/ha respectively in line with the rate of K2O from 0 kg/ha to 200 kg/ha. However respond MR 269 is better than MR 278. During the main season 2012/2013, MR 269 and MR 278 showed a positive response when N rate was 200 kg/ha and 100 kg/ha but differ in the rate of K. However the main season MR 269 shows a lower yield performance compared to MR 278. These findings suggest that, MR 269 can achieve optimum yield potential at the rate of 100 kg N/ha but different of K at the rate of 200 kg K2O/ha and 100 kg K2O/ha respectively in the off-season and main season. While the MR 278, N and K2O at the rate of 200 kg/ha showed optimum yield in the off-season. Meanwhile, at the rate of 100 kg N/ha and 200kg K2O/ha in the main season can provide optimum yield.